102 research outputs found
Complex and sustained quantum beating patterns in a classic IVR system: the 3¹5¹ Level in S₁ p-difluorobenzene
Using picosecond time-resolved photoelectron imaging we have studied the intramolecular vibrational energy redistribution (IVR) dynamics that occur following the excitation of the 3151 level which lies 2068 cm-1 above the S1 origin in p difluorobenzene. Our technique, which has superior time resolution to that of earlier studies but retains sufficient energy resolution to identify the behavior of individual vibrational states, enables us to determine six distinct beating periods in photoelectron intensity, only one of which has been observed previously. Analysis shows that the IVR dynamics are restricted among only a handful of vibrational levels, despite the relatively high excitation energy. This is deduced to be a consequence of the high symmetry and rigid structure of p-difluorobenzene
Perivascular Fat and the Microcirculation: Relevance to Insulin Resistance, Diabetes, and Cardiovascular Disease
Type 2 diabetes and its major risk factor, obesity, are a growing burden for public health. The mechanisms that connect obesity and its related disorders, such as insulin resistance, type 2 diabetes, and hypertension, are still undefined. Microvascular dysfunction may be a pathophysiologic link between insulin resistance and hypertension in obesity. Many studies have shown that adipose tissue-derived substances (adipokines) interact with (micro)vascular function and influence insulin sensitivity. In the past, research focused on adipokines from perivascular adipose tissue (PVAT). In this review, we focus on the interactions between adipokines, predominantly from PVAT, and microvascular function in relation to the development of insulin resistance, diabetes, and cardiovascular disease
‘Measuring’ Physical Literacy and Related Constructs: A Systematic Review of Empirical Findings
BACKGROUND:The concept of physical literacy has received increased research and international attention recently. Where intervention programs and empirical research are gaining momentum, their operationalizations differ significantly.OBJECTIVE:The objective of this study was to inform practice in the measure/assessment of physical literacy via a systematic review of research that has assessed physical literacy (up to 14 June, 2017).METHODS:Five databases were searched using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Protocols guidelines, with 32 published articles meeting the inclusion criteria. English-language, peer-reviewed published papers containing empirical studies of physical literacy were analyzed using inductive thematic analysis.RESULTS:Qualitative methods included: (1) interviews; (2) open-ended questionnaires; (3) reflective diaries; (4) focus groups; (5) participant observations; and (6) visual methods. Quantitative methods included: (1) monitoring devices (e.g., accelerometers); (2) observations (e.g., of physical activity or motor proficiency); (3) psychometrics (e.g., enjoyment, self-perceptions); (4) performance measures (e.g., exergaming, objective times/distances); (5) anthropometric measurements; and (6) one compound measure. Of the measures that made an explicit distinction: 22 (61%) examined the physical domain, eight (22%) the affective domain; five (14%) the cognitive domain; and one (3%) combined three domains (physical, affective, and cognitive) of physical literacy. Researchers tended to declare their philosophical standpoint significantly more in qualitative research compared with quantitative research.CONCLUSIONS:Current research adopts diverse often incompatible methodologies in measuring/assessing physical literacy. Our analysis revealed that by adopting simplistic and linear methods, physical literacy cannot be measured/assessed in a traditional/conventional sense. Therefore, we recommend that researchers are more creative in developing integrated philosophically aligned approaches to measuring/assessing physical literacy. Future research should consider the most recent developments in the field of physical literacy for policy formation
CrossTalk proposal: de novo capillary recruitment in healthy muscle is necessary
Perfusion is a principal determinant ofmuscle function, as is evident fromimpaired myocardial contraction duringischaemia. Perfusion determines soluteexchange between blood and tissues, andis tightly regulated by local and centralmechanisms. Here, we discuss how exerciseand insulin regulate muscle perfusion,focusing on the control of microvascularsurface area or ‘recruitment’
[(NHC)Pd(allyl)Cl] Precatalysts in The Hiyama Reaction of Aryl Chlorides with Aryl Trimethoxysilanes: A Study in Side Reactions
Palladium N-heterocyclic carbene (NHC) complexes of the
general
type [(NHC)Pd(allyl)Cl] are investigated as precatalysts in the Hiyama
reaction of aryl chlorides with phenyl trimethoxysilanes. High yields
of biaryls products are obtained from aryl chlorides featuring electron
withdrawing groups using precatalysts coordinated to NHC ligands with
sterically smaller wingtip groups (IMes and SIMes). Unactivated aryl
chlorides appeared to be poor substrates in this reaction. A mechanistic
proposal which we believe explains this poor activity is outlined
based on in situ analysis by 19F NMR spectroscopy where
PhSi(OMe)3 reacts nonproductively with fluoride, halting
the reaction prematurely, via at least two different pathways
Helical Poly(quinoxaline‐2,3‐diyl)s Bearing 1,2,3‐Triazole Pendants: Synthesis by CuAAC and Use as Reusable Abnormal NHC Ligands in Gold Catalysis
Contraction stimulates nitric oxide-independent microvascular recruitment and increases muscle insulin uptake
- …